I looked in FFA but what file will let me adjust AP circle thickness and what is the values available when adjusting as some are to thicc when playing and some are to thin.
The thickness of the approach circle is not adjustable in skin.ini or in-game. You'd have to edit the image itself "approachcircle.png" or "approachcircle@2x.png". If you don't know how to do this, you can just take your favourite approach circle from a skin and move it to yours.